Weaving machine

ABSTRACT

A weaving machine comprises two sheets of warp threads which are momentarily held in diverging planes to form a weaving shed, and a main blowing nozzle arranged in a position at one side of such shed to introduce a weft thread through such shed by propelling the weft thread by means of a fluid discharged from the nozzle. A reciprocable reed comprises a plurality of blades arranged parallel to the direction of reciprocation, each blade having a notch on its beating edge, such notches being aligned and forming a tunnel less than 8 mm. in diameter which in the retracted position of the reed has one end aligned with the main blowing nozzle. An air injector carried by the reed is mounted in the other end of such tunnel and is adjustable longitudinally of the tunnel to accommodate various widths of cloth being woven, such air injector having a central suction channel arranged to receive the head end of a weft thread propelled through the channel by the main blowing nozzle in order to maintain tension on the weft thread during the beating up movement of the reed.

1451 Apr. 29, 1975 O United States Patent 11 1 Vermeulen 1 WEAVINGMACHINE [7S] lnventor: Geert Jan Vermeulen, Deurne. Netherlands [73]Assignee: Ruti-Te Strake B.V.. Deurne, Netherlands [22] Filed: May 7,1973 [21] Appl. No.1 357,842

[30] Foreign Application Priority Data May 10. 1972 Netherlands 7206367[52] US. Cl. 139/127 P; 139/194; 139/370 [51] Int. Cl. D03d 47/28: D03d47/34 [58] Field of Search 139/127 R. 127 P. 194. 139/370 [56]References Cited UNITED STATES PATENTS 3.399.701 9/1968 Tcstrake 139/127P 3.532.138 10/1970 Schlappi 139/370 3.658.098 4/1972 Van Mullekom139/194 3.744.533 7/1973 Yuno et al. 139/194 I f! 11 111111 I 8 PPrimary E.\'amin 'rHenry S. .laudon Attorney. Agent. or Firm-Marshall &Yeasting [57] ABSTRACT A weaving machine comprises two sheets of warpthreads which are momentarily held in diverging planes to form a weavingshed. and a main blowing nozzle arranged in a position at one side ofsuch shed to introduce a weft thread through such shed by propelling theweft thread by means of a fluid discharged from the nozzle. Areciprocable reed comprises a plurality of blades arranged parallel tothe direction of reciprocation. each blade having a notch on its beatingedge. such notches being aligned and forming a tunnel less than 8 mm. indiameter which in the retracted position of the reed has one end alignedwith the main blowing nozzle. An air injector carried by the reed ismounted in the other end of such tunnel and is adjustable longitudinallyof the tunnel to accommodate various widths of cloth being woven. suchair injector having a central suction channel arranged to receive thehead end of a weft thread propelled through the channel by the mainblowing nozzle in order to maintain tension on the weft thread duringthe beating up movement of the reed.

2 Claims. 2 Drawing Figures WEAVING MACHINE BACKGROUND OF THE INVENTIONThe invention relates to a weaving machine of the type in which atransport tunnel for the weft threads is defined by a plurality ofblades. each having a substantially U-shaped notch. which are movablealong with the reed. and in which the weft threads are introduced fromone side of the weaving shed to the other through said tunnel by theaction of a flowing fluid discharged from of a main blowing nozzlepositioned at one side of the shed. tensioning means being provided atthe other side of the shed adapted to tension at weft thread that hasbeen inserted into the shed and to keep said thread in a tensioned stateduring the beating up movement.

Such a weaving machine is known. In this machine the tensioning meanscomprise a mechanism formed by a catching means movable along with thereed and by a clamping means cooperating with said catching means duringthe beating up movement of the reed. Another method of catching andtensioning the weft yarn inserted through the shed is described inBritish Patent specification l.t)88.749. according to which a pluralityof catching threads. running parallel to the warp threads. are used,which are moved apart and brought together again in synchronism with theopening and closing of the shed so as to receive the end of the weftyarn extending beyond the shed. and are subsequently twisted togetherfor trussing said ends and thereby keeping the weft yarn taut. In stillanother weaving machine of the type above referred to a special catchingand tensioning lever mechanism for tensioning the wefts is mountedlongitudinally adjustable on the reed. This mechanism has the advantagethat it may be adjusted to different weaving widths. but it is of arelat'nely complicated construction and control.

A common disadvantage of the known devices for tensioning wefts is thatthey do not provide for compensating for changes in length anddifferences in elasticity.

SUMMARY OF THE INVENTION Now according to the invention the tensioningmeans is constituted by an air injector carried by the reed and having acentrally disposed suction channel aligned with the end of the transporttunnel remote from the main blowing nozzle.

The great advantage of an air injector as a tensioning means for thewefts is that its tensioning effect is independent of any changes inlength and variations as a result of differences in elasticity which areautomatically compensated. while the weft end which remains extendingbeyond the selvage after the weft has been bound in. is automaticallyretracted from the injector by the beating movement of the reed. Thetensioning means are of a simple construction. without moving parts andwithout special control means.

It is to be noted that tensioning a textile thread by means of an airinjector is already generally known per However. the problem with an airinjector when applied to the purpose in view is that this air injectormust be able to catch the head end of a weft inserted into the shed.from a plurality of positions which may be taken by the weft head endwithin the shed.

In view of the latter circumstance the suction nozzle which usually ismounted at the side of the machine remote from the weft blowing nozzle.for receiving the head end of an inserted weft and for later ondischarging the cut end of said weft. generally has relatively largedimensions. The weft cannot be drawn sufficiently tensioned by such alargely dimensioned suction nozzle; therefore in well-known weavingmachines. apart from such a suction nozzle there are additional meansfor tensioning the weft.

Therefore. in accordance with the present invention it is essential thatthe position of the head end of the weft at the end of the weftinserting phase be rather accurately defined. so that is will besufficient to use an air injector which is of relatively smalldimensions and therefore is indeed suitable as a tensioning means. andoperates with an economically justified air consumption. This conditionof a relatively accurately defined weft head end position is satisfiedby the present weaving machine in which the transport of the weftthrough the shed occurs through a transport tunnel defined by suitablyshaped blades. more particularly a tunnel which is delimited by aplurality of blades moving along with the reed. which tunnel dependenton the weaving width cooperates with one or more auxiliary blowingnozzles spaced along the weaving width.

The latest developments in a weaving machine of the last mentioned typeled to an embodiment in which the wefts are transported through a tunnelhaving a cross section less than 8 mm. wide. Now exactly below thislimit the application of an air injector as the device for tensioningthe \vefts has appeared to be not only practically but also technicallyfeasible.

Therefore. the invention relates to a weaving machine in which the crosssections ofthe reed tunnel and the suction aperture of the air injectorrespectively are less than about 8 mm. wide.

A special advantage of the air injector as a weft tensioning means isobtained when used in combination with a weft detecting means. For weftdetecting purposes it has been proposed. e.g. in British patentspecification l.236.346 to use a light source and a photoelectricreceiver cooperating therewith. The light source emits a single lightray in a transverse direction through the tunnel-like transport path ofthe weft. Since the position of the weft in its transport path. asindicated above. may strongly vary. it is necessary with such adetection device to constrain movement of the inserted weft transverseto the weft direction in order to be sure that the inserted weft willpositively interrupt the light ray. Now when an air injector is used asa means for tensioning the weft this restriction of the transversemovement is automatically obtained. Extensive experiments have indeedshown that each air injector imparts a certain twinning to the weftresulting in making the weft balloon-shaped. by this minimal balloonshape the weft tensioned in the relatively small cross section of theair injector according to the invention will in any case interrupt thelight ray which is e.g. directed diametrally through said cross section.Preferably the light source and the photoelectric receiver are providedin the wall of the discharge channel of the air injector.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of partof the reed of a pneumatic weaving machine. provided with a device fortensioning the wefts according to the invention and FIG. 2 is alongitudinal section through the tensioning device according to theinvention. in which at the same time the electrical diagram of the weftdetection means is shown.

DESCRlPTlON OF THE PREFERRED EMBODIMENT In FIG. 1 a tunnel-liketransport channel is formed in the weaving shed 3. constituted by theupper and low er warp threads 1 and 2. and by the reed blades 5 eachhaving a substantially L-shaped notch opening towards the beating upline 4. which blades are encased in the reed beam 6.

The reed comprising the reed beam with the blades 5 is in HO. 1 in itsretracted position. in this position the transport tunnel formed by thereed blades 5 is located opposite the weft inserting nozzleschematically indicated at 7. which is adapted to introduce a weft bymeans of an airjet into the said tunnel. Usually a weaving loom shouldbe able to weave cloths of different widths. Therefore the reedgenerally extends at the side remote from the weft blowing nozzle 7beyond the corresponding side edge of the cloth by a varying distance.In the end portion ofthe reed tunnel extending beyond the side edge ofthe cloth the air injector indicated 8 has been provided which ismounted. adjustable in the direction of the cloth width. on the reedbeam 6 by means of a connecting bracket 9. The airinjector 8. which isshown in FIG. 2 in longitudinal section. has a construction which isknown per se and corresponds to that of the weft blowing nozzle. Theinjector serves to receive the weft launched by the weft insertingnozzle 7 and also to tension it and keep it in a tensioned state duringthe heating up movement of the reed. To this end the injector 8 issupplied with air at the same time as or very shortly after the nozzle 7and at least up to and including the end phase of the beating upmovement ofthe reed. The connection point for a flexible air hose isindicated at 9'. When the reed is advanced to its beating position theend of the weft inserted into the cloth is retracted from the injector 8and this may be received in a suction nozzle in a manner known per se.and may subsequently be cut by a cutting device. Of course it is thenimportant that the end portion of the weft extending beyond the edge ofthe cloth be not longer than the distance through which the reed andtherefore the air injector 8 move between the beating up position andthe retracted position. Only then will the evtending weft end be freedwith certainty from the injector 8.

The air injector 8 further comprises the components ot'a weft detectingdevice. namely a light source 10 and a photoelectric receiver ll.

The light source it] may be constituted by a miniature incandescentlamp. a Ga-As diode or similar small light source and is provided eitherdirectly in the wall of the discharge tube 8' of the injector 8. or mayhe in o tical communication with a fibre optics sunk into a radial borein that wall. The photoelectric receiver 1] e.g. comprises a photo diodewhich is provided diametrally opposite to the light source 10 in thewall of the discharge tube 8'.

Although the light ray emitted diametrally by the light source 10through the discharge tube 8' only covers a very narrow portion of thecross section (being about 3 mm. wide) of that tube. a weft caught bythe injector 8 will yet. as explained above. interrupt said light raywith certainty. Asa consequence of that interruption the photo diode 11issues a signal as a sign that indeed a weft has been inserted from theother side of the machine. This signal may. as indicated in the diagramaccording to FIG. 2, be converted by an amplifier 12 into an electricsignal necessary to keep the electric circuit of the drive of themachine energized.

I claim:

1. A weaving machine comprising two sheets of warp threads which aremomentarily held in diverging planes to form a weaving shed. and a mainblowing nozzle arranged in a position at one side of such shed to propela weft thread through such shed by means of a fluid discharged from saidnozzle. wherein the improvement comprises a. a reciprocable reedcomprising a plurality of blades arranged parallel to the direction ofreciprocation. each blade having a notch in its beating edge. suchnotches being aligned and forming a tunnel having a crosssection lessthan 8 mm. wide which in the retracted position ofthe reed has one endaligned with the main blowing nozzle.

b. an air injector nozzle which is located wholly within said tunnel andhas a central suction channel arranged to receive the head end of a weftthread propelled through said tunnel by the main blowing nozzle in orderto maintain tension on the weft thread during the beating up movement ofthe reed. and a bracket on which the injector nozzle is mounted. whichis slidably secured to the reed and is arranged to locate the injectornozzle in the end of said tunnel remote from the main blowing nozzle ina longitudinally adjusted position to accomodate the width of clothbeing woven.

2. A weaving machine according to claim I. in which at detecting deviceis provided for detecting the wefts inserted into the transport tunnelcomprising a light source and a photoelectric receiver. characterized inthat said detecting device is provided in the wall of the injector,

1. A weaving machine comprising two sheets of warp threads which aremomentarily held in diverging planes to form a weaving shed, and a mainblowing nozzle arranged in a position at one side of such shed to propela weft thread through such shed by means of a fluid discharged from saidnozzle, wherein the improvement comprises a. a reciprocable reedcomprising a plurality of blades arranged parallel to the direction ofreciprocation, each blade having a notch in its beating edge, suchnotches being aligned and forming a tunnel having a cross-section lessthan 8 mm. wide which in the retracted position of the reed has one endaligned with the main blowing nozzle, b. an air injector nozzle which islocated wholly within said tunnel and has a central suction channelarranged to receive the head end of a weft thread propelled through saidtunnel by the main blowing nozzle in order to maintain tension on theweft thread during the beating up movement of the reed, and c. a bracketon which the injector nozzle is mounted, which is slidably secured tothe reed and is arranged to locate the injector nozzle in the end ofsaid tunnel remote from the main blowing nozzle in a longitudinallyadjusted position to accomodate the width of cloth being woven.
 2. Aweaving machine according to claim 1, in which a detecting device isprovided for detecting the wefts inserted into the transport tunnelcomprising a light source and a photoelectric receiver, characterized inthat said detecting device is provided in the wall of the injector.